As someone with years of experience of pushing the battery-life of laptops to the limit, the iPad was something of a revelation. If we ignore the time I stupidly left the Smartcover auto on/off engaged while it was in a bicycle pannier on a London to Paris cycle ride, I’ve literally never run out of power.

However, since I was reviewing the Digital Treasures Powerflask, I thought I would look at the company’s Props Power Case at the same time. The concept is a simple one: a protective case with a built-in battery. Plug your iPad into the case, and the case provides the power…